Complex Vertebral Malformation (CVM)
July 24, 2001 Select Sires Memo
MEMORANDUM
TO: Board of Directors, Member Managers, Member Marketing Directors,
Member Communications Coordinators, Select Sires Staff, John Schouten
FROM: Dave Thorbahn, general manager, Select Sires Inc.
SUBJECT: Update About Complex Vertebral Malformation (CVM)
DATE: July 24, 2001
While there still is more to be learned about Complex Vertebral
Malformation (CVM), I'm writing to update you on some of the research
efforts that are underway.
Select Sires has worked with Dr. David Steffen, veterinary pathologist
at the University of Nebraska-Lincoln, to research three calves that
were born dead and exhibited symptoms of CVM. He has confirmed that
each did have CVM and he is storing their tissue for future research.
Two of the calves have been parent-identified using DNA technology;
one was sired by 7HO5234 Ricecrest BRANDON-ET*TL and out of a
7HO3847 Ameldin II Pontiac HUNTER*TL dam, the other was sired by
7HO6530 Schaufine Amel DICTATOR-ET and out of a 1HO1523 Ca-Lill BELLTONE
dam. The third calf has not been parent-verified, but is believed to be
sired by 9HO2266 Chapel-Bank Elton FARMER*TL.
We submitted tissue samples from the three sires of these calves to the
diagnostic laboratory in The Netherlands, which has been licensed by
the Danish researchers who discovered CVM. The laboratory has declared
FARMER to be a carrier of this condition. The laboratory said that
BRANDON and DICTATOR are "most probably a carrier of CVM. A final
conclusion is possible only if material from the dam or sire is provided."
As part of a research project funded by the National Association of
Animal Breeders that is being conducted by the Select Sires embryo
division, we have purchased the dam of the BRANDON calf. The project
involves the superovulation and flushing of cows that have produced
CVM-affected calves, breeding them to bulls that have sired a CVM-affected
calf. Through the first 90 days of gestation we will use ultrasound to
examine the fetuses in-utero. The pregnancies will be carried through
to term. In addition to learning more about the mode of transmission of
this genetic condition, we hope to identify CVM's economic impact.
The dam of the BRANDON calf is in an ongoing flushing program. She was
flushed first in May with no embryos resulting, with her second
flushing scheduled this month. The dam of the DICTATOR calf is milking
heavily and being held open. Once she can be dried off successfully,
we will purchase her as part of this research project.
At a minimum, we will need 15 to 20 pregnancies before we can begin
drawing conclusions from this research. However, it is also possible
that we will need as many as 60 to 70 full-term pregnancies to better
understand the science behind this condition. While the best-case
scenario is that preliminary results could be available late this year,
more realistically it will be next year before this project provides
scientifically valid results.
Attached, for your reference, is a news release recently distributed
by NRS (a sister company to Holland Genetics) reporting that CVM is
caused by a single gene. Holstein Association USA has requested and
received details about the research protocol. Interpreting the research,
it does include a substantial number of pregnancies and the approach
appears to be sound. The biggest disappointment is that once again the
researchers have chosen to rush this information to the press rather
than following the time-tested process of first submitting the data
and analysis for peer review.
The original research identifying CVM, which was conducted in Denmark,
has been published in a peer-reviewed journal, The Journal of Veterinary
Diagnostic Investigation (July 2001 issue). The researchers had submitted
the manuscript for publication on Jan. 25, 2001. The article describes
the symptoms of the condition and concludes that is it is likely a
genetically transmitted defect. No specifics about the mode of inheritance
are provided in this article. If you would like a copy of this seven-page
scientific article, just let me know.
So what does all of this mean? While new information regarding CVM is
now available, there still are important questions to be answered. It
is important to give new information serious consideration, but we
also should not panic. As the facts about CVM become available, the
breeding community will need to make tough decisions about individual
animals, remembering that the "CVM gene" is just one among 10,000
genes that influence the performance of Holsteins.
One thing that could help us advance the fastest in our understanding
of this condition is to add more cows that have produced CVM-affected
calves to the ongoing NAAB research project. Whatever you can do to
help identify calves that may have CVM would be a great help.
While we are waiting for additional peer-reviewed research to provide
concrete answers, it is likely that dairy producers may come to you
with questions about CVM. Please feel free to share this memo with
members who have questions. If a member wants to discuss the topic
in more depth, you can direct him/her to Chuck Sattler,
Dr. Don Monke or me.
Select Sires Inc., 11740 U.S. 42 North, Plain City, Ohio 43064 / Phone: (614) 873-4683 Fax: (614) 873-5751
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